National Aluminium Company Limited (NALCO) is a Central Public Sector Enterprise under the administrative control of Ministry of Mines. NALCO is an integrated company involved in the excavation of Bauxite and production of Alumina and Aluminium. NALCO also had a captive power plant to ensure supply of power to the Smelter and Alumina Refinery. A Performance Audit was conducted covering the production performances of the Mines, Alumina Refinery, Smelter Plant and Captive Power Plant of NALCO for the period from 2012-13 to 2016-17. The objectives of the Performance Audit were to assess whether the Mines and the Captive Power Plants were operating in the manner and at the level required for the optimum operation of the Alumina Refinery and Smelter Plants respectively. The Performance audit was also to see whether the Alumina Refinery and Smelter Plants were operating at the required capacity to produce the desire product in a cost effective manner.